Generally, in jet-propelled small-sized boats which glide over water surface, a single person rides the boat in a standing posture on the floor deck of the boat with his hands gripping the handle bars to rotate them for steering so as to control a steering cable extending from a handle post via the boat interior to the stern to swing the steering nozzle of the jet propelling device (water jet pump) for steering the boat.
During riding, the rider intentionally changes the position of application (position of the center of gravity of the boat) of the foot pressure (rider's body weight) on the floor deck of the boat, thus causing the boat not only to glide over water surface in a curve but also to jump above water surface or, reversely, to dive. In this manner, the rider steers the boat to change its posture as desired while enjoying the high technique required to make such change or competing in such technique, a fact attributable to the increasing popularity of this type of boats particularly among the young.
In a conventional boat of this type, however, as is clear from FIGS. 9 through 11, a handle post 1 is pivotally connected at its front or lower end to the boat a by a horizontal shaft 2 to allow its rear or upper end to swing in arcuate movement. A handle bar attaching plate 5 pivotally connected through a vertical shaft 4 to a base board 3 belonging to said rear or upper end which swing in such arcuate movement is integrated with a handle bar b at the middle as by welding; therefore, when the level of the upper or rear end of the handle post increases as the arcuate movement of said handle post 1 proceeds, the rider has to shift his position toward the front of the floor deck 6 or, reversely, if the level of the handle bar b decreases, he is forced to stand at a position nearer to the rear of the floor deck 6.
Thus, the standing position of the rider is consequently influenced by such changes in the level of the handle post 1, and the steering operation is limited in changing the position at which the foot pressure is applied to the boat. As a result, it becomes difficult to steer the boat a to change its posture, as desired. Further, the capability of the boat to cope with the rider's physical build and steering technique which vary from rider to rider is degraded.
In this connection, according to U.S. Pat. No. 4,745,872 previously proposed by the present inventor, structurally, the attaching bracket A of the handle bar 16 is divided into a front bracket 17 and a rear bracket 21. Since the position at which the rear bracket 21 is connected to the front bracket 17 is adjustable, the rear bracket 21 can be slid for adjustment to the rider's physical build and steering technique which vary from rider to rider; thus, the disclosed arrangement is advantageous in that the aforesaid problem has been solved in this manner.
However, in the case of the invention of U.S. Pat. No. 4,745,872, a pair of grips 27 at the handle bar 17 are integrated with the opposed ends of the straight extensions of said bar and extend substantially horizontally in rearwardly diverging form as seen in a plan view. Therefore, the rider assumes a steering posture in which the backs of the hands holding the grips 27 are turned upward, with the armpits opened.
As a result, the foot pressure resulting from the rider's body weight cannot be applied to the boat 10 effectively and rationally from the standpoint of human engineering, and it is also difficult to steer the boat in a stabilized manner while exerting an effective resistance to the force which tends to throw away the rider's body during the revolving of the boat 10. It should be said that the disclosed arrangement leaves room for improvement in the feeling of integration between the rider and the boat and is difficult to operate.
Further, since the handle post 13 is swung around the axis of the horizontal shaft 14 at its front or lower end, its tilt angle with respect to the floor deck 11 also varies. Since the handle bar 16 is rigidly attached to the rear or upper end of the handle post through the base board 15 and the attaching bracket A, the posture and the direction of extension of the grips 27 on the handle bar 16 also vary, and there will arise another problem that the rider fails to stably hold the grips without adversely affecting his steering posture. And such problems likewise arise in the conventional product shown in FIGS. 9 through 11.